Sustainable Production of Fuels and Chemicals via Designing New Catalysts and Processes

As the cost of renewably derived (e.g., solar and wind) electricity continues to decrease given the rapid progress in technology and economies of scale, there is a growing interest in fuels and chemicals electrosynthesis in a clean, sustainable, and distributed manner. This approach can provide an alternative pathway to the traditional fossil fuel-driven processes as well as the storage of surplus renewable energy in the form of fuel at times of excess supply in the grid. Electrification of fuels and chemicals on a large scale requires an effective electrocatalyst that generates fuel/chemicals with a high yield and efficiency.

(photo) electrochemical nitrogen reduction reaction (NRR) for ammonia synthesis provides an attractive alternative to the long-lasting thermochemical process (Haber-Bosch) in a clean, sustainable, and decentralized way if the process is coupled to renewably derived electricity sources. Ammonia is a critical agrochemical and essential precursor for pharmaceutical and industrial products. Ammonia is also an attractive carbon-neutral liquid fuel to store intermittent renewable energy sources when supply exceeds demand in the grid as well as for power generation due to the compound’s high energy density (5.6 MWh ton-1) and hydrogen content (17.6 wt.%). Electrification of ammonia synthesis on a large scale requires an effective electrocatalyst that converts N2 to NH3 with a high yield and efficiency. The selectivity of N2 molecules on the surface of the catalyst has been demonstrated to be one of the major challenges in enhancing the rate of photo-electrochemical NRR in an aqueous solution under ambient conditions. Improving the design of electrocatalysts, electrolytes, and the electrochemical cell is required to overcome the selectivity and activity barrier in electrochemical NRR.

The scientific thrusts of my research to address a critical obstacle to achieving the overarching goal of distributed ammonia synthesis will be built upon nanomaterials synthesis for catalyst discovery of NRR in photo-electrochemical apparatus and ex-situ and operando spectroscopy and microscopy investigations to pinpoint underlying mechanisms in catalysis.

Thrust 1: Discovery of new photo-electrocatalyst materials for selective and efficient catalysis of NRR.

Thrust 2: Design and fabrication of advanced reactors that enable us to study redox processes in photo-electrochemical systems.

Thrust 3: ex-situ and operando spectroscopy and microscopy to probe the reaction mechanism and intermediate species relevant to NRR at the electrode-electrolyte interfaces.

Our research program in this field of study is currently funded by the US National Science Foundation (NSF) and the Georgia Research Alliance (GRA). We gratefully acknowledge our past and current funding agencies and sponsors.